{ "id": "2110.09203", "version": "v2", "published": "2021-10-18T11:41:18.000Z", "updated": "2022-07-10T13:03:58.000Z", "title": "Twisted K-theory in motivic homotopy theory", "authors": [ "Elden Elmanto", "Denis Nardin", "Maria Yakerson" ], "comment": "corrections in Lemma 5.10", "categories": [ "math.AG", "math.AT", "math.KT" ], "abstract": "In this paper, we study twisted algebraic $K$-theory from a motivic viewpoint. For a smooth variety $X$ over a field of characteristic zero and an Azumaya algebra $\\mathcal{A}$ over $X$, we construct the $\\mathcal{A}$-twisted motivic spectral sequence, by computing the slices of the motivic twisted algebraic $K$-theory spectrum as a twisted form of motivic cohomology. This generalizes previous results due to Kahn-Levine where $\\mathcal{A}$ is assumed to be pulled back from a base field. Our methods use interaction between the slice filtration and birational geometry. Along the way, we prove a representability result, expressing the motivic space of twisted $K$-theory as an extension of the twisted Grassmannian by the sheaf of \"twisted integers\". This leads to a proof of cdh descent and Milnor excision for twisted homotopy $K$-theory.", "revisions": [ { "version": "v2", "updated": "2022-07-10T13:03:58.000Z" } ], "analyses": { "keywords": [ "motivic homotopy theory", "twisted k-theory", "twisted motivic spectral sequence", "study twisted algebraic", "smooth variety" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }